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Finding the Fourth Proportional to 1,138.61, 1,571.34 and 641.43

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Solution

The fourth proportional to 1,138.61, 1,571.34 and 641.43 is: 885.21

Step by Step Solution

  1. Step 1: Write the proportion equation
    1,138.61 : 1,571.34 = 641.43 : x
  2. Step 2: Convert to fraction form
    1,138.61/1,571.34 = 641.43/x
  3. Step 3: Cross multiply
    1,138.61x = 1,571.34 × 641.43
  4. Step 4: Simplify right side
    1,138.61x = 1,007,904.62
  5. Step 5: Solve for x
    x = 1,007,904.62/1,138.61
  6. Step 6: Final answer
    x = 885.21

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Double scale
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1.5x scale

Why These Related Problems?

These problems maintain the same ratio (1.38) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.